overwrite jqGrid ajax mechanism, send json to backend instead of submitting a form. datatype should be "json" "xml" "script" postData is data you wanna send ajaxGridOptions is ajax configuration of jQuery serializeGridData is a function having only one argument which is postData you provided, it should return a Serialized data(e.g. String)

grid-submit-json.js

self.grid.jqGrid("setGridParam", {
	serializeGridData: self.serializeData,
	url: self.executionUrl,
	datatype: "json",
	ajaxGridOptions: {
		cache: false,
		contentType: "application/json",
		processData: false,
		type: "POST"
	},
	postData: {
		reportId: self.reportId,
		userCondition: self.userCondition.toJSON(),
		criterionType: self.getCriterionTypeValue()
	}
});
self.grid.trigger("reloadGrid");